Mineral oil lubricating composition, and an improvement agent therefor and its method of preparation



MINERAL OIL L momma co AND an nvnu'r aonu'r 'rns- FOB IT 0B OF PREP aHerschel a... s in.

c n, sdown TEON 0rd, and oy L. assignors to G Oil Corporation,Pittsburgh, Pa., a corporation of Pelvania No Drawing.

This invention relates to improvement agents for lubricating oils andmethods of mag the same.

In the lubrication of internal combustion engines of all types,particularly when severe operating conditions are encountered, plain mineral oils often prove unsatisfactory due to the attendant deposition onthe engine surfaces. such as cylinder walls, pistons and rings ofvarnish, gum or sludge? This effect is particularly serious in modernengines operating under severe conditions, such as Diesel engines,aviation, truck and tank engines. The problem has become increasinglyserious due to the trend toward higher emciency, or higher power outputper unit weight per engine, reduction in the amount of oil employed inthe lubricating system of the engine and other conditions which tend toaccelerate the deteriorating influences on mineral lubricating oil.

The formation of so-called varnishes or sludges on engine surfaces isdue to oxidation or olymerization sheets (or both) on the lubri eatingoils, as well as to like effects can from the products of combustion ofthe fuels, which find their way by leakage into the engine cranlz caseand other parts of the engine.

The presence of these substances is disadvantageous for many reasons. Inparticular the oil and fuel oxidation products tend to increase ringsticking and production of deposits on piston surfaces and in fixedparts of the combustion chamber. Sludges are formed in the crank case ofthe engine and the rate of corrosion of bearing surfaces is increasedespecially with bearing alloys of the types now in use.

Petroleum oils intended for use under the severe conditions describedare almost always compounded with a-mixture of substances each intendedto counteract one or more of the unedesirable efiects noted. Thesesubstances, which fall into a wide variety of chemical classificationsare known by the general term improvement agents or addition agents.Prepa ration ofsatisiactory compounded lubricants is a matter ofconsiderable dimculty. Some of the agents are of low potency in that arather large amount has to be added to achieve certain de= siredresults. Often two or more agents are more or less incompatible witheach other; and their rather low solubility in general further adds tothe dificulties in preparing a useful lubricant.

One object of the present invention is the provision of an improvementagent for engine oils which can be'incorporated in petroleum oils ineffective proportions and which imparts to the oil a plurality offunctions.

Another object is 'the'provision of such an agentiin'the-form of asolution in petroleum lubricating oils, which serves the functions oiApplication April 9, 19 12, Sl No. 438,324

(oi. sea-so) oil; for example, particles of carbonaceous matter thatfind their way into the crank case oil by passing the piston rings whichcannot possibly bemade absolutely tight. Another object is the provisionof a new improvement agent capable of increasing the solubility ordispersibility of other agents such as straight soaps or the like, whenit is desired also to add such compounds to the 011.

According to this invention, new improvement agents for lubricating oilscapable of achievin these and other objects are prepared from certainalkylated phenols (oleflne-phenol reaction products) by simultaneouslyreacting phosphorus oxychloride (POCls) and phosphorus sesquisulfide(P483) with the alkylated' phenols to form complex acid reactionproducts, which in turn are treated with lime (or other metal oxide orhydroxide), producing stable complex metallocompounds of alwlated phenolesters of phosphorus acids, of the character described in more detailbelow. That is, as shown post, the new agents are prepared fromalkylated phenols containing at least one branched chain alkyl group.Likewise, as there shown, in preparing the new agents, such alkylatedphenols are simultaneously reacted with phosphorus oxychloride andphosphorus sesquisulfide under controlled conditions to produce acidreaction productsthereof, and the acid reaction products so metalloderivatives thereof are obtainedj the stable, oil-soluble improvementagent so obtained being separated from the unreacted metal oxides andhydroxides and other insoluble compounds. The polyvalent metal compoundsso obtained, particularly the diand tri-valent metal compounds andmixtures thereof, are useful for the present purposes.

The so-prepared agents or metallo-compounds, in solution in lubricatingoils provide four functions which are useful and advantageous inlubricants. (1) By virtue of the combined polyvalent metal (e. g.calcium, etc.) suspending or detergent properties are imparted, as wellas resistance to ring sticking, (2) the combined phosphorus impartsanti-bearing-corrosion and antiring-sticking properties as well aspressurecarrying properties, (3) the combined sulfurserves to givepressure carrying properties to the oil and to retard corrosion of alloybearings, and

portant advantage in that in addition to being very oil-soluble itself.it acts to disperse in min- ]eraloils other improvement agents which areof Thus according to the invention there is provided a compound which,dissolved in oil, imparts thereto all the many desirable features whichwe wish to obtain. It is in a form which is so soluble in motor oils ofall types and degrees of refinement that we can incorporate any desiredproportions to form a clear solution in lubricating oils, even in mosthighly refined and most parafllnic of the heavy aviation oils, such asare specified for the most severe and exacting aviation service.

It is known that highly parafilnic oils, refined to the high degreedesired to secure such desired properties as low carbon-forming eflectsand high viscosity indices (improved viscosity temperaturerelationships) are relatively poor solvents for decomposition productsformed in use. Also there is increased tendency to induce bearingcorrosion. In this invention these undesirable properties of such oilare done away with by the use of moderate amounts of our new compoundingagent having cumulatively all the desired properties in the way of readysolubility in the oils and other advantageous effects mentioned above.We can employ very highly refined paraifinic-type aviation oils thathave the desired superior physical characteristics as regards theparticular property, and, at the same time avoid any undesirable effectswhatever from the use 01' such oils. In other words, the addition of ourcompound which is soluble in all proportions in the heavy highly refinedparafflnic oils enables us to secure all the properties desired in theway oi. the oils of superior performance characteristics, as well as theefl'ects of detergency,

avoidance of ring sticking, varnish formation, sludge formation andcorrosion of alloy bearings that might otherwise be encountered, as wellas secure the desired efiect of retarding oxidation due to the use ofmore highly refined oils of less tendency to oxidize combined with theuse of a compound which actually retards oxidation.

Another important field of utility 'for the invention is in Diesellubricating oils. Heretofore it has been considered best to usenaphthene-type oil dosed with certain compounding agents which are ofundesirably low efliciency and which moreover are not readily solubleeven in the most naphthenic type of Coastal oils. This has often beennecessary to make a compromise even for the Coastal oils of greatersolubility effect for compound agents between the degree of refining andthe solubility effect for the addition agents. It is quiteunsatisfactory for most of these agents to use even a moderately refinedparafiin type oil, as all or part of the addition agents heretofore usedwill often separate from the oil upon standing. For these reasons Diesellubricating oils hitherto prepared have been rather unsatisfactory inthat they employ low grade oils of less degree of resistance tooxidation than would otherwise be desirable. With the present invention,we prepare an improved oil which performs satisfactorily in Dieselengines by employing a highly refined paraflln-type of oil with controlof ring sticking efi'ects and sludge formation and detergency eilects byincorporation of the pres.- ent compound in any desired proportion.

The new improvement agent has another imthemselves relatively insoluble.For example, in

' accordance with the present invention 1 per cent or more of calciumoleate or aluminum stearate can be'dissolved in oil to form a stable andcom mon dispersion with the aid of an equal quantity of the new agent.Thus the new agent is sometimes useful when and where its ownantioxidant and dispersing properties are not required for its value indissolving other agents.

The new agent is conveniently prepared in the 'form of a concentratedoil solution which can readily be stirred into an oil to prepare a com-'pound lubricant.

In preparing the new agent, the base material is advantageouslyalkylated phenols which themselves have good antitoxidant properties. Aconvenient source for this base material or principal reactant is thephenol-olefin reaction products prepared as described in U. S. Patent2,149,759 issued March 7, 1939, to Troy Lee Cantrell. For instance, anadvantageous material is a heartcut" of such phenol-olefin reactionproducts, prepared from the 20-80 per cent cut separated by steam orvacuum distillation; vacuum distillgtion being preferred. This heart-cutis a mixture of liquid, semi-liquid and crystalline alkylated phenols.It is soluble in all proportions in lubricating oils and gasoline, andsoluble in most organic solvents and insoluble in water and NaOHsolutions. It has the following properties:

Gravity A. P. I 18.0-24.0 Sp. gr., 60/60 F 0.9465-09100 Viscosity, S. U.V.:

100 F 60-000 Pour F --30 to +15 Color, N. P. A 1.0-1.5 Free phenol";"percent" Nil Mineral acidity,

S03 equivalent percent Nil Distillation, A. S. T. M. D 86-38:

Over point F 375-380 End point F 525-540 10% at F 415-450 Thisphenol-olefin reaction product contains varying amounts of4-tertiary-butyl-phenol, 2- tertiary-butyl=4-secondary-butyl phenol,2,4-clitertiary butyl phenol, 2,6 di-tertiary-butyl-isecondary butylphenol, 2,4,6-tri-tertiary-butyl phenol, 2,6-di-tertiary-butyl 4 methylphenol, 4,6-di-tertiary-butyl-2-methyl phenol,4,6-cli-tertiary-butyl-2-methyl phenol and other alkylated phenolscontaining a branched chain alkyl group attached to the phenyl nucleusthereof. All these alkylated phenols have good antioxidant propertiesand are useful in making our new improvement agents. As a class they maybe represented by the following general formula:

wherein R, R and R" represent hydrogen or an alkyl group, at least onebranched chain alkyl group being present. Those containing secondary ortertiary alkyl groups are particularly advantageous for the presentpurposes.

In proceeding in accordance with the first stage of the presentinvention, such alkylated phenols are brought into reaction withphosphorus oxychloride and phosphorus sesquisulfide. in the desiredproportions, the mixture of reactants being heated to facilitatereaction. Upon heating the mixture, the three reactants vigorouslyinteract, forming complex alkylated phenyl esters of phosphorus acids,wherein the alkylated phenyl groups thereof contain at least onebranched chain alkyl substituent. Advantageously, the reaction may beeffected at temperatures between 230 and 550 F., and is usually carriedout at about 450 F. Likewise, the proportions of the reactants, namelythe alkylated phenols, P0013 and Piss, may be varied and controlled toproduce reaction products advantageously for the present purposes.Usually we employ 15 to 25 parts of phosphorus oxychloride and 1 to 5parts of phosphorus sesquisulfide per 100 part of the alkylated phenol.The reaction products so obtained readily react with metal oxides andhydroxides, forming metal salts of these alkylated phenol esters.

In forming such metal salts, the reaction products or esters describedante may be treated with various metal compounds. For instance, valuableimprovement agents are readily obtained by heating such products withhme. lime (quick or hydrated) is added in theproportions of about 5 to25 parts (figured as CaO) 'mr 100 parts of the reaction product and themixture heated at a temperature of 22M00 F, for about three hours. Thereaction mixture is'filtered and is then ready for use.

In lieu of ordinary lime, dolomitic limes, magnesia or magnesiumhydroxide can be employed. Likewise other polyvalent metallic oxides orhydroxides, such as alumina or zinc oxide may be employed in preparingour metallo-derivatives or metal salts of these allrylated phenyl estersof phosphorus acids. That is, various metal compounds may be employed inthe practice of this invention.

The improvement agents so obtained are oi complex constitution, evenwhen a single alkylated phenol, such as 2,6-di-tertiary-butyl-4- methylphenol, etc., is employed. Further, us= ing mixtures of allrylatedphenols, such as the heart-cut of the olefin-phenol reaction productsdescribed ante, mixtures of metallo-derivatives of alkylated pheuylesters are obtained. As stated, these are advantageous in the practiceof this invention.

That is, our improvement agent obably a mixture of similar or analogouscompounds and may contain varying proportions of the severalconstituents, namely combined phosphorus, sulfur, metal, etc., combinedin a complex metallo compound. As a matter of fact, we vary the relativeproportions of the reactants, depending upon the particular propertiesdesired. There is considerable flexibility in the proportion of calciumor other metal added and combined for securing a range of detergency,anti-ring sticking, and solid suspension effects; or in the amount ofcombined phosphorus as required to obtain the desired anti-ring stickingand anti-corrosion efiects. That is, these constituents of ourimprovement agents can be varied at will. For instance, the metalcontent can be made to vary over relatively wide limits.

That is, in practice we vary the proportions of the several reactants inaccordance with the particular properties desired. After the desiredcombinations have been efiected, the reaction product is filtered toremove insoluble compounds In doing so.

and is then ready for use. The filtered materials are readily solubleinlubricating oil.

in preparing improved lubricants, the optimum proportion of the agent tobe introduced into lubricating oils depends on the severity of theservice conditions and the degree to which the oil itseli" tends to formgum or varnish. 0rdinarily from 0.25 to 5.0 per cent by weight of theimprovement agent on the oil is suitable. The improved lubricants soobtained have the advantageous properties described ante and aresuperior lubricants.

The preparation and use of our improvement agents is further illustratedin the iollowing illustrative examples which are typical but notllmitative of this invention.

Example L-in a specific exple illustrative of one advantageous way ofpreparing an agent within the purview oi the invention, 1684 pounds ofthe above described phenol-olefin reaction product were mixed with 59lbs. oi P483 and 61% pounds of POCis. The ture was agitated and heatedat also 3?. for a period oi 4% hours.

The reaction product so obed was a mixture of edkylated phen'yl estersoi phosphorus acids, which reamiy react with metal oxides andhydroxides. This particular, reaction product had the followingproperties:

Gravity ....A. P. 1-- o.e Specific gravity, 6ii/6ll F lnd'l'ilViscosity, S. U. V.:

109 F %8 Color, N. P. A 6.5 Sulfur, Carius per cent" coo Phosphorus,Gal-ins do $.92 Chlorine, Carina do 10.80 Ash as sulfate do 0.4.75

This reaction product was diluted with approximately an equal weight ofmineral lubricating oil, namely, a Texas oil having a Saybolt viscosityoi ice at F. The mixture containing 85.? pounds of the reaction productand 86.7 pounds of mineral oil was stirred in an open iron vessel and7.1 pounds of hydrated lime added. This mixture was agitated and heatedto 350 F. for 3 hours. The solution of improvement agent in oil soobtained was then aed with a filter aid and filtered. The filtrate hadthe following identifying properties:

Gravity A. P. I... 14.9 Sp. gin, fifi/6il Fu $3665 Viscosity, S. U. ii:

loo F 567 g -30 Color, N. P. A 3.5 sulfur, B -per cent 0.2? Chlorine,arius ..do .61! Phosphorus, Carius do 3.44 Carbon residue do 6.11 g

Ash as sulfate d0- It is an excellent improvement agent for lubrinickelin lieu of calcium may be prepared by substituiing a molecularequivalent proportion of nickel carbonate for the hydrated calcium limein the above example.

New improvement agents or concentrates oil for use inDiesel engines.

' ciurn derivative gave superior lubrication engines under serviceconditions. I

Example lV.--An improved lubricating oil was thereof containing otherdivalentmetal salts or derivatives can be prepared in a similar mannerby selecting a suitable reactive divalent metal compound for reactionwith the alkylated phenol esters of the phosphoric acids. salts of theseesters are effective improvement agents. In general, polyvalent metalderivatives of the alkylatedphenyl esters of the phosphorus acidsprepared by the methods described ante, are useful and advantageousimprovement agents for lubricating oils. 1 1 v A series of lubricatingoil compositions was prepared by dissolving in a straight engine oilvarv I ious quantities of the improvement agentsof the presentinvention. These compositions were submitted to various tests and all ofthem gave improved lubricating qualities. Typical compositions and theirpreparation are illustrated in the following examples:

Example Ill-An improved lubricating oil was prepared by dissolving 2.0per cent of the preparation of ExampleI in a high grade lubricating thiscalin such The improved composition containing prepared by dissolving312 per cent of the preparation of Example II in a high grade lubricatThe viscosities and their conventional identifyin characters of theseimproved compositions,

together with those of the base oil were as follows:

Improved lubricant Base oil

Example Example III IV Gravity A P I 26. 5 26. 5 2G. 8 lScOSlL} S 100 l,819 1. 761 l, 764 210 F.. 122.3 111.4 ll5.8 Viscosity index. 98 91 89Flash, C... 525 510 495 Fire, OC.. F.- 595 585 590 Pour 0 +5 (-olor, N.P. A 5. 5 5. 5 7. 5 Sulfur, B "poi-cent 0. 36 0. 23 Carbon residue. .do.0. 46 0. 43 0.55 Ash as sulfate do n. 24 0.388 Copper strip test, 212F., 3 hrs 1 Passes.

In order to evaluate their tendency to cause ring sticking in engines,these compositions were subjected to a motor service test in thelaboratory, using a standard Waukesha-CFR crankcase with special L headtype cylinder block, coupled to a cradle-type electric dynamometer. Thisengine has a bore -of /14 inch, a stroke of 4 inches, and a compressionratio of 4.7:1. The piston is of cast iron with four compression ringsand one oil-control ring, all located above the wristv pin. Three litersof the oil to be tested are placed in the crankcase. The engine is thenrun at 900 R. P. M. with the spark and the airfuel ratio adjusted togive maximum power, and the coolant temperature is maintained at 350 F.At the end of 25 hours running, the engine is stopped and dismantled andthe piston is examined. The performance of the oil is then ratedaccording to the condition of the piston, in keeping with the followingscale, in which the For instance, tin v rating number increases as theston condition becomes worse:

5--T0p, 2nd and oil rings completel stuck. '6'Condition No. 5 with 3rdand 4th rings partly stuck,

In the above test the rating of the several compositions were asfollows:

(.umposition Improved uil Base oil EX. III EN. RatingNm. 4 1 2 Y withthe following results:

Composition Similar improved results are obtained with lubricating oilscontaining small amounts of other metal salts of these esters ofalkylated phenols.

While the improvement agent of the present invention has been describedin reference to compounding engine lubricating oils for the primarypurpose of preventing ring sticking, its field of usefulness is notconfined to that application. It can be used in oils wherever itsproperties may be desired. Sometimes it is used for its dispersivepowers on other agents, when its own antioxidant and detergentproperties are not needed.

That is, another important advantage of the agents of the presentinvention is that .in addition to being highly soluble in oilsthemselves, they are effective to disperse in mineral oils certain soapswhich are of themselves diflicultly soluble, for example, calcium oleateor aluminum stearate. Again, sulfurized sperm oil soap is a desirableaddition agent to oils, but its low solubility prevents incorporation ofmore than a rather small quantity in paraffin base oils. By the presentinvention 1 per cent or more of such soap can be dispersed in oil, toform a stable dispersion by including an equal amount of the newimprovement agents of this invention. Thus in the practice of thepresent invention, our new agents may be used in conjunction with otherpreviously known addition agents, in compounding lubricating oils toimprove their properties. Thus in the practice of the present invention,various embodiments thereof may be employed in addition to theillustrative embodiments shown ante.

What we claim is:

1. A process of preparing an improvement agent for lubricatingoils,'from alkylated phenols containing at least one branched chainalkyl These compositions were alsosubjected to the Y phorous oxychlorideand 1 to 5 parts of phos-.

phorus sesquisulfide, by weight, at temperatures between 280 and 550 F.until substantially all of the phosphorus oxychloride and phosphorusses-- quisulfide have reacted and acid reaction produces thereof areobtained, and converting the acid reaction products so obtained intostable, substantially neutral metal derivatives thereof by furtherheating said acid reaction products with a reactive metal compound of aclass consisting of the oxides and hydroxides of a polyvalent metal, theamount of said reactive polyvalent metal compound being suiiicient toneutralize the acidity of said reaction products, and the mixture beingheated to temperatures between 220 and 400 F. until stable,substantially neutral, metal derivatives thereof are obtained, andseparating the unreacted metal oxides and hydroxides and other insolublecompounds from the nil-soluble improvement agent so obtained.

2. The method of claim 1 wherein said reactive metal compound is lime.

'3. The method of claim 1 wherein said reactive metal compound is adivalent metal compound.

4. The method of claim 1 wherein the alkylated phenols employed as thestarting material are phenol-olefin reaction products comprising amixture of alkylated phenols containing secondary and tertiary alkylgroups.

5. The method of claim 1 wherein the said acid reaction products of thealkylated phenols are heated with the said polyvalent metal compounds inproportions of 5 to parts 'of the reactive metal compound per 100 partsof said acid reaction products.

6. The method of claim 1 wherein said acid reaction products are dilutedwith mineral 01] prior to the treatment with the said polyvalent metalcompounds, and wherein the oil solution of stable; substantially neutraloil soluble metallo compounds so obtained is filtered to removeunreacted metal oxides and hydroxides and other insoluble compounds.

'7. A process of preparing an improvement agent for lubricating oils,from alkylated phenols containing at least one branched chain alkylgroup which comprises heating parts of said alkylated phenols with 10 to25 parts of phosphorus oxychloride and 1 to 5 parts of phosphorussesquisulfide, by weight, at temperatures between 280 and 550 F. untilsubstantially all of the phosphorus oxychloride and phosphorussesquisulfide have reacted and acid reaction products thereof areobtained, diluting the acid reaction product .agent so obtained toremove unreacted metal oxicPes and hydroxides and other compoundsinsoluble in the oil.

8. An improvement agent soluble in petroleum oil and capable ofinhibiting formation of gum, varnish, and sludge in engines, comprisingthe stable, oil-soluble, substantially neutral metallo compoundsobtained by the process of claim 1.

9. An improved lubricating composition comprising a major amount of amineral lubricating oil and a small proportion of the stable,oil-soluble, substantially neutral metallo compounds obtained by theprocess of claim 1,. the amount of said oil-soluble improvement agentbeing suflicient to inhibit the formation and deposition of gum, varnishand sludge in engines and to disperse such deposits when present.

10. An improvement agent, for lubricating oils, comprising the stable,substantially neutral prodnot of the process of claim '7, said productbeing readily soluble in petroleum oils and capable of inhibitingformation of gum, varnish and sludge inengines.

I-IERSCHEL G. SMITH. TROY L. CAN'I'REIL.

